Drill bit



.April 15, 1952 H. w. WALLACE 2,593,229

DRILL BIT Filed. NOV. 14, 1947 2 Sl'iEETS-SHEET 1 22 IzgZ E a M II Q 2 April 1952 H. w. WALLACE 2,593,229

7 DRILL BIT.

Filed NOV. 14, 1947 2 SI'IEETS-SIIEET 2 Men M Maura Patented Apr. 15, 1952 2,593,229 DRILL BIT Harry W. Wallace, Windsor, Ontario, Canada,

assignor to Wheel Trueing Tool Company, Detroit, Mich., a corporation of Delaware Application November 14, 1947, Serial No. 786,082

This invention relates to a rotary drill bit, and more particularly to a core or solid type rotary drill bit in which diamonds are set singly in protuberances formed in the drilling face of the bit.

The drill bits to which my invention pertains are used in drilling rock or other earth formations, as for instance in the drilling of oil wells. Such drill bits are removably mounted on the end of a core barrel which forms a part of the drilling shaft. As the shaft is rotated about its axis,-the drill bit effects its cutting and abrading action upon the material against which it is forced by the weight of the shaft above it. In the case of a core bit, the core cut by the bit passes upwardly through the core barrel and is removed through the hollow shaft. At the same time, circulating fluid is forced downwardly through the core barrel around thecore for discharge over the working face of the bit to carry away the cuttings and abraded particles.

It has heretofore been proposed to make diamondimpregnated and diamond set bits for use in earth and rock drilling operations. In some of the larger type of diamond set drill bits for use in oil well drilling operations as much as several hundred carats of diamonds have been used in a single drill hit. As a consequence of the use of. such a large weight of diamonds in a single drill bit, the cost has been very high'and the danger of the bit being accidentally destroyed in use has been a serious consideration.

In accordance with my present invention, I am able to use a smaller weight of diamonds for the same type and size of drill bit, and also smaller individual diamonds, and still accomplish the same effective cutting. This is accomplished by a novel and improved construction and arrangement of the drilling face of the bit. The

drilling face is provided with protuberances symmetrically arranged in substantially radially extending rows and also, preferably, in spirally extending rows. Each of the protuberances is preformed as an integral part of the matrix metal that constitutes the drilling face of the bit, and each protuberance is of a well-defined shape, such as pyramidal, conical, segmental spherical, or the like, to provide more or less of an apex. A single diamond, or diamondparticle is set in each such apex so as to project therefrom. Instead, how- 5 Claims. (01. 255-72) properly set in the matrix metal so as to be firmly held therein, and for this purpose a matrix metal such as disclosed in thePetrie Patent No. "2,210,039 may be employed, since by the process of that patent firm adherence between. the diamonds and the tungsten metal is obtained. It is also contemplated, however, that other types of matrix metal, such, for instance, as the cemented carbide type, can be used. The mound of matrix metal in which each diamond is mounted supports the diamond in a free-cutting position and enables the use of smaller diamonds by virtue of ;the mass of the supporting metal. This means a smaller diamond area of contact with the material being drilled and sharper individual diamonds or diamond particles. Less weight need be applied to the bit and the bit may be rotated at a slower speed and yet the bit will cut at a higher rat of fore been used.

penetration than diamond set bits of previous construction.

Further, by virtue of the construction and arrangement of the drilling face of the bit the circulating fluid during the drilling operation can pass freely around each individual diamond particle to insure the clearing away of the cuttings in a most effective manner and also to insure the cooling of each diamond as it engages the rock or other material to be drilled. The smaller diamonds when arranged as described withra single diamond set in the apex of each protuberance accomplish the drilling just as effectively as larger diamonds arranged as formerly and with greater economy in the use of the diamonds.

' It is therefore an important object of this invention to provide a diamond set drill bit of novel and improved construction that is just as eifective as more expensive drill bits that have hereto- It is a further important object of this invention to provide a drill bit having a drilling face provided with well-defined and symmetrically arranged protuberances in each of which is seta ever, of using relatively large diamonds of a carat or over in weight, that have previously been used in drill-bits of diflerent construction, smaller diamonds ofthe order of from two to ten diamonds '2 toythe carat are employed; Each diamond is used in the drilling operation is able to pass freely around each individual diamond to clear the cutexercise a cooling'effect upon each diamond as it engages the material being drilled.

Other and-further important objects of this invention will be apparent from the disclosures in the specification and the accompanying drawings.

On the drawings:

Figure 1 is a top plan view of a drill bit em;- bodying the principles of myinvention.

ing an exposed cutting portion. The more effective use of a lesser weight of diamonds and diamonds of smaller sizes is believed to be largely due to this arrangement. It also makes possible the use of a larger volume fiow of circulating fluid to carry off the cuttings from each individual diamond more efiiciently and thus maintain the diamond in a freer cutting condition.

As compared with a drill bit in which diamonds of a carat or over are set directly in the body of the matrix metal, rather than in spaced protuberances of the matrix metal, the drill bit of my invention with pre-formed protuberances and water grooves makes more efiective use of smaller diamonds of one-half carat or less. This is largely because the smaller diamonds are sharper and remain so during their useful life, and because they are freer cutting due to the provision of pre-formed grooves forming clearances surrounding each diamond. The result is that the bits of my invention may be rotated more slowly, as for instance at from 50 to 100 R. P. M. as against over 100 R. P. M. for former type bits, and less weight need be placed on my bits, roughly one-half as much, to cause the bits to cut at a higher rate of penetration.

In bits of my invention, the diamonds accomplish the drilling solely by virtue of their cutting and abrasive action. Diamonds could not be satisfactorily used in bits where they would be subjected to percussive impacts since the shock of such impacts would shatter the relatively brittle diamonds. Consequently, the bits of my invention are of the rotary type in which the individual diamonds move only with the bit as a whole and remain in substantially continuous frictional contact with the material being drilled. Under such circumstances, the diamonds are not subjected to sudden and severe impacts. In order to distinguish from roller bits and other bits in which there is an impact action between the cutting elements and the material being drilled and in which diamonds could not be satisfactorily used, the bits to which my invention pertains are referred to in the claims as plain rotary type drill bits. The term diamond particle, as used in the claims, is intended to mean a whole diamond, or any integral diamond fragment.

It will, of course, be understood that various details of construction may be varied through a wide range without departing from the principles of this invention and it is, therefore, not

the purpose to limit the patent granted hereon otherwise than necessitated by the scope of the appended claims.

I claim as my invention:

1. A plain rotary type drill bit having a convex end working face provided with pyramidal protuberances arranged in substantially radially extending rows with water grooves therebetween, and a single diamond particle set in each of said protuberances to project from the apex of such protuberance.

2. A plain rotary type drill bit having a drilling face comprising inner and outer reaming faces and an intermediate convex face provided with well-defined similar protuberances each having all side faces converging to an apex, and a diamond particle set in each apex.

3. A core drill bit having a drilling face provided with pyramidal protuberances arranged in rows that extend substantially radially with radially extending water grooves therebetween and also arranged in spiral rows, and a single diamond particle set in each protuberance to project from theapex thereof.

4. A core drill bit having an annular drillin face provided with pyramidal protuberances symmetrically arranged in well-defined. radially extending and spirally arranged rows and a single diamond particle set in each protuberance to project from the apex thereof.

5. A core drill bit having an annular drilling face provided with pre-formed pyramidal protuberances symmetrically arranged in well-defined radially extending and in arcuate rows, the radially extending rows being separated by water grooves and the arcuate rows providing cuttings receiving grooves therebetween, and a single diamond particle set in each protuberance to project from the apex thereof.

HARRY W. WALLACE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 545,808 Great Britain June 15, 1942 

